Refrigerant measuring and warning device and sensing element thereof

ABSTRACT

A refrigerant measuring and warning device includes a casing, at least one sensing element, and a detection circuit. The casing forms connectors, which are connected together by a conduit, to selectively connect to sources of refrigerant to be detected. The sensing element has an enclosure forming a connector at an end for connection with the conduit and an interior chamber communicating the connector via a pressure-dropping necked passage, a pressure detection chip and a thermocouple arranged at a top of the chamber for detecting pressure and temperature of the refrigerant to be detected. The detection circuit is housed in the casing and stores multiple sets of reference temperature and pressure for different type of refrigerants for comparison with the detected pressure and temperature, both data being displayed on a display device for visual observation and comparison. The detection circuit receives settings of alarm thresholds for the detected pressure and temperature via a keypad whereby a warning unit may issue a warning sound or voice alarm when the detected pressure and temperature reach/exceed the thresholds.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to a refrigerant measuring and warning device and a sensing element thereof, and in particular to a refrigerant measuring and warning device that features comparison and detection of refrigerant pressure and temperature, digital display, and alarm by exceeding of thresholds.

2. The Related Arts

Air conditioner and refrigeration facility provides air conditioning and refrigeration by means of refrigerant that is filled in and circulates through the air conditioner or the refrigeration facility through compression-expansion cycles. Conventionally, a meter is used to detect the pressure of the refrigerant filled into the air conditioner or refrigeration system. The meter is an analog device and can only provide a single reading of the detected pressure of the filled refrigerant. Visual observation of the meter reading is not very precise and can results in significant error. Further, the conventional meter cannot detect temperature of the filled refrigerant. In addition, the conventional meter cannot provide references for the detected pressure of the refrigerant, which often causes troubles to the operator in carrying out refrigerant filling and measuring.

Moreover, in case that multiple refrigerant equipments need to be monitored simultaneously during the refrigerant filling process, additional operators are required to perform a one-to-one monitoring and operation. This certainly increases the costs. Besides, the problems of incorrect reading of the meters mentioned above also induce impreciseness for the operation of refrigerant filling that may be very important in certain applications.

An example of the conventional technical of refrigerant filling operation is disclosed in Taiwan Utility Model Publication No. M82088, which is also filed by the present applicant.

SUMMARY OF THE INVENTION

Thus, an object of the present invention is to provide a refrigerant measuring and warning device comprising: a casing forming connectors for selectively connecting sources of refrigerant to be detected, the connectors being connected by a connection conduit; at least one sensing element connected to the connection conduit that connects the connectors of the casing to detect pressure and temperature of refrigerant and supply detected signals of the pressure and temperature; and a detection circuit comprising a microprocessor, a memory, a display device, a keypad, a warning unit, and a power supply device, the microprocessor having a built-in input signal conversion circuit, which is coupled to the sensing element to receive and convert the detected pressure and temperature signals for the microprocessor, the memory storing multiple sets of reference refrigerant pressure and temperature, the keypad being operable to enter selection instruction and warning instruction of pressure and temperature to the microprocessor and the display device being operable to show the detected refrigerant pressure and temperature and the reference pressure and temperature on the display for comparison, the warning unit being coupled to the microprocessor to issue an alarm when the detected refrigerant pressure and temperature reach/exceed preset warning thresholds, the power supply device powering the microprocessor, the memory, the display device, the keypad, and the warning unit.

Another objective of the present invention is to provide a sensing element comprising: an enclosure having an end forming a connector for connecting a supply of refrigerant to be detected, the enclosure forming an interior chamber, which communicates the connector with a pressure-dropping necked passage to convey the refrigerant to be detected, in a pressure dropped condition, into the chamber; a pressure detection chip arranged at a top of the chamber to detect pressure of refrigerant supplied into the chamber of the enclosure; and a thermocouple arranged at the top of the chamber to detect temperature of the refrigerant supplied into the chamber of the enclosure.

The refrigerant measuring and warning device allows for precise measurement, display, and monitoring of the pressure and temperature of the refrigerant to be detected and can provide multiple sets of reference pressure and temperature that are directly displayed on a display device, for comparison with the detected refrigerant pressure and temperature. Further, the device of the present invention allows for issuance of alarms when the detected pressure and temperature reach/exceed preset thresholds of pressure and temperature. Thus, the filling of the refrigerant in an air conditioner or refrigeration facility can be performed in a more precise and controlled manner. Besides, the problems of errors caused by visual observation of the conventional analog meter can be eliminated.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to clearly show and make better comprehension of these and other features and advantages of the present invention, the present invention will now be described by way of examples, with reference to a preferred embodiments illustrated in the drawings, in which:

FIG. 1 shows a perspective view of a refrigerant measuring and warning device constructed in accordance with the present invention;

FIG. 2 shows, in cross-section, the construction of a casing and detection connectors of the refrigerant measuring and warning device of the present invention;

FIG. 3 is an exploded view, partially broken, of a sensing element in accordance with a preferred embodiment of the present invention;

FIG. 4 is a cross-sectional view of the sensing element shown in FIG. 3;

FIG. 5 is an exploded view, partially broken, of a sensing element in accordance with another embodiment of the present invention;

FIG. 6 is a block diagram of a detection circuit of the refrigerant measuring and warning device in accordance with the present invention;

FIG. 7 is a block diagram of an input signal conversion circuit that forms in part a microprocessor of the detection circuit shown in FIG. 6;

FIG. 8 shows an example layout of a display device and a keypad of the refrigerant measuring and warning device of the present invention;

FIG. 9 shows another application of the sensing element of the present invention; and

FIG. 10 is a block diagram of a detection circuit of the refrigerant measuring and warning device in accordance with another embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to the drawings and in particular to FIGS. 1 and 2, a refrigerant measuring and warning device constructed in accordance with the present invention, generally designated with reference numeral 100, comprises a casing 10, at least one sensing element 20, and a detection circuit 30. The casing 10 is provided with a plurality of detection connectors 11, 12, 13, which provide connection with refrigerant to be detected. The detection connectors 11, 12, 13 are connected together with a connection conduit 14.

Also referring to FIGS. 3 and 4, the sensing element 20, which is constructed in accordance with a first embodiment of the present invention, is shown. The sensing element 20 comprises an enclosure 21, a pressure detection chip 22, and a thermocouple 23. An end of the enclosure 21 forms a connector 211 and an opposite end forms an inner-threaded opening 212. The connector 211 connects to the connection conduit 14 that is arranged inside the casing 10. In the embodiment illustrated, two sensing elements 20 are provided and the connectors 211 of the sensing elements 20 connect to respective ends of the connection conduit 14. It is apparent that the sensing element 20 can be connected to any position along the connection conduit 14 without departing from the spirit of the present invention. The inner-threaded opening 212 forms thread 212 a on an inside wall (not labeled) thereof to engage and retain a threaded closing member 212 b inside the opening 212.

The enclosure 212 forms an interior chamber 213, which communicates the connector 211 with a pressure-dropping necked passage 214. The passage 214 has an inside diameter that is much smaller than those of the connector 211 and the interior chamber 213. The refrigerant to be detected is supplied into the interior chamber 213 through the passage 214 after being subject to pressure dropping caused by the necked passage 214.

The pressure detection chip 22 is mounted to a bottom face (not labeled) of the threaded closing member 212 b. The pressure-detection chip 22 comprises a detection end 221 and an opposite end forming terminals 222. The detection end 221 faces toward bottom of the chamber 213 to detect the pressure of the refrigerant supplied into the chamber 213 and, in response thereto, generates a pressure detection signal corresponding to the detection of pressure. The terminals 222 extend through the threaded closing member 212 b to output the detected pressure detection signal.

The thermocouple 23 is arranged on the bottom face of the threaded closing member 212 b and faces toward the bottom of the chamber 213 to detect the temperature of the pressure-dropping refrigerant that is supplied into the chamber 213 and generates a corresponding temperature detection signal. The thermocouple 23 has a pair of terminals 231 for outputting the temperature detection signal and the terminals 231 extend through the threaded closing member 212 b.

Referring to FIG. 5, which shows another embodiment of the present invention, in which the pressure-detection chip 22 and the thermocouple 23 are mounted on a single control circuit board 24, the single control circuit board 24 has pressure-detection signal terminals 241 that are connected to the terminals 222 of the pressure-detection chip 22 and temperature-detection signal terminals 242 that are connected to the terminals 231 of the thermocouple 23 and the terminals 241 and 242 extend through the threaded closing member 212 b.

Referring to FIGS. 6 and 7, wherein FIG. 6 shows a block diagram of the detection circuit 30 of the refrigerant measuring and warning device 100, which illustrates only an example of the circuit that embodies the present invention, and should not be construed as limitation to the present invention, the detection circuit 30 is arranged inside the casing 10 and comprises a microprocessor 31, a memory 32, a display device 33, a keypad 34, a warning unit 35, and a power supply device 36. The microprocessor 31 is built therein with an input signal conversion circuit 311, which can be of any known circuit, and may comprise, in the embodiment illustrated, amplifiers 311 a, 311 b, 311 c, a level transformation circuit 311 d, and an analog-to-digital converter 311 e, as shown in FIG. 7. The amplifiers 311 a, 311 b are connected to the terminals 222 of the pressure-detection chip 22 of the sensing element 20 to amplify the pressure detection signal of the refrigerant supplied to the chamber 213 and apply the amplified signal to the analog-to-digital converter 311 e where the amplified signal, which is originally analog, is converted into corresponding digital signal for output.

The level transformation circuit 311 d can be of any know type, and comprises, in the embodiment illustrated, a circuit comprised of transistors and/or thyristors for transformation of voltage level of an input signal. The level transformation circuit 311 d is coupled to the terminals 231 of the thermocouple 23 of the sensing element 20 to receive the temperature detection signal of the refrigerant supplied to the chamber 213 and transforms the voltage level of the temperature detection signal. The level transformation circuit 311 d is also coupled to the amplifier 311 c, which amplifies the transformed temperature detection signal and applies the amplified and transformed temperature detection signal, which is originally analog, to the analog-to-digital converter 311 e to provide a corresponding digital signal for output.

The analog-to-digital converter 311 e is coupled to the microprocessor 31 to supply the digital signals of pressure and temperature of the refrigerant to the microprocessor 31 for subsequent processing.

Software or programs for converting and displaying the refrigerant pressure and temperature are built in the microprocessor 31 for processing the digital data of the refrigerant pressure and temperature from the analog-to-digital converter 311 e to form data that can be displayed on the display device 33.

Sets of different standard data or reference data of refrigerant pressure and temperature are stored in the memory 32 that is coupled to the microprocessor 31 whereby the microprocessor 31 may issue instructions to the memory 32 for access or retrieve a selected set of standard data of refrigerant pressure and temperature from the memory 32.

Also referring to FIG. 8, the display device 33 can be of any type, and may comprise, in the embodiment illustrated, a liquid crystal display (LCD) device. Apparently, other equivalent display devices, such as light-emitting diode (LED) display and cathode ray tube (CRT) display, are within the scope of the present invention. The display device 33 comprises a LCD drive circuit 331, a display panel 332, and a backlight drive circuit 333. The LCD drive circuit 331 and the backlight drive circuit 333 are coupled to the microprocessor 33 to receive from the microprocessor 33, the refrigerant pressure and temperature of the refrigerant supplied to the chamber 213, as well as those data retrieved from the memory 32. The data are displayed on the display panel 332. FIG. 8 illustrates an example of the display panel 332, which comprises a left section that shows the pressure and the temperature of the refrigerant detected and a right section that shows corresponding reference data or standard data of refrigerant pressure and temperature for immediate comparison.

The keypad 34 is coupled to the microprocessor 31 and can be of any type, such as thin-film touch-control keypad that is taken as an example for explanation purposes herein. FIG. 8 shows an example of the keypad 34, comprising buttons 341, 342, 343, 344, 345, 346, 347, 348, which are a power button, a unit system conversion button, a refrigeration type selection button, a reset button, a backlight setting display button, a memory button, a memory clearing button, and a warning setting button, respectively, for manual input of instruction or data related to power, conversion of unit system, selection of refrigerant type, resetting, backlight setting display, memory, memory clearing, and warning setting. Apparently, this button can be configured in different ways. It is noted that the warning setting button 348 is provided for selective actuation and setting of warning levels of refrigerant pressure and temperature to the microprocessor 31, which serve as thresholds for issuing alarm for the pressure and temperature of the refrigerant supplied to the sensing element 20.

The warning unit 35 is coupled to the microprocessor 31 and is connected to an alarm device 351, which can be of any type, and is embodied as a buzzer in the embodiment illustrated. When the pressure and/or temperature of the refrigerant to be detected reach the thresholds or warning settings given by the warning setting button 348 of the keypad 34, the microprocessor 31 signals the warning unit 35 to actuate the alarm device 351, which then gives off an alarm, which can be a single tone or a voice alarm or any combination thereof.

The power supply device 36 can be of any type, and is comprised of a battery set of direct current, as shown in the embodiment illustrated. Other equivalent power supplies, such as direct-current adaptor for a household electric main, are apparently within the scope of the present invention. The power supply device 36 supplies power to the sensing element 20, the microprocessor 31, the memory 32, the display device 33, the keypad 34, and the warning unit 35.

In practical use of the refrigerant measuring and warning device 100, setting and actuation of power, conversion of unit system, selection of refrigerant type, resetting, backlight setting display, memory, memory clearing, and warning setting are operated through the buttons 341, 342, 343, 344, 345, 346, 347, 348 of the keypad 34. The refrigerant measuring and warning device 100 provides a display that allows for comparison between the detected refrigerant pressure and temperature and reference or standard pressure and temperature and also an alarm may be issued by the alarm device 351 that is actuated by the warning unit 35 under the control of the refrigerant measuring and warning device 100, if the detected values of the pressure and temperature reach/exceed preset thresholds.

Referring to FIG. 9, which shows another application of the sensing element 20, in the application, the sensing element 20 is housed in a casing 10′. The casing 10′ also houses the detection circuit 30. A display 33′ is provided on the casing 10′ to display detected refrigerant pressure and temperature and reference or standard pressure and temperature, as well as thresholds for pressure and temperature. A plurality of buttons 341 a, 342 a, 343 a, 344 a are provide on a surface of the casing 10′ for performing setting and operation of power, backlight displaying, switching of refrigerant pressure and temperature, and switching of function to thereby provide a simplified, single-input refrigerant measuring and warning device 100′ that still realize the above discussed functions of comparison and display of the detected refrigerant pressure and temperature and reference or standard pressure and temperature and the thresholds of pressure and temperature, as well as setting of the thresholds of pressure and temperature.

Referring to FIG. 10, which shows another embodiment of the detection circuit 30, in the illustrated detection circuit 30, the pressure detection chip 22 of the sensing element 20 is coupled to a constant current source 37. The constant current source 37 is connected to a power supply device 36 to provide a constant current to the pressure detection chip 22 in order to eliminate errors caused by variation of current induced by external temperature or temperature rise occurring in the circuit whereby more precise detection of the refrigerant supplied to the sensing element 20 by the pressure detection chip 22 can be effected.

Although the present invention has been described with reference to the preferred embodiments thereof, it is apparent to those skilled in the art that a variety of modifications and changes may be made without departing from the scope of the present invention which is intended to be defined by the appended claims. 

1. A refrigerant measuring and warning device comprising: a casing forming connectors adapted to selectively connect sources of refrigerant to be detected, a connection conduit connecting among the connectors; at least one sensing element connected to the connection conduit inside the casing to detect pressure and temperature of refrigerant from the refrigerant source and supply detected signals of the pressure and temperature; and a detection circuit comprising a microprocessor, a memory, a display device, a keypad, a warning unit, and a power supply device, the microprocessor having a built-in input signal conversion circuit, which is coupled to the sensing element to receive and convert the detected pressure and temperature signals into digital data that is applied to the microprocessor, the memory storing multiple sets of reference refrigerant pressure and temperature, the keypad being operable to enter selection instruction and warning instruction of pressure and temperature to the microprocessor and the display device being operable to show the detected refrigerant pressure and temperature and the reference pressure and temperature on the display for comparison, the warning unit being coupled to the microprocessor to issue an alarm when the detected refrigerant pressure and temperature reach/exceed preset warning thresholds, the power supply device powering the microprocessor, the memory, the display device, the keypad, and the warning unit.
 2. The device as claimed in claim 1, wherein the input signal conversion circuit of the detection circuit comprises a plurality of amplifiers, a voltage level transformation circuit, and an analog-to-digital converter.
 3. The device as claimed in claim 2, wherein the input signal conversion circuit of the detection circuit comprises a circuit comprised of transistors and/or thyristors.
 4. The device as claimed in claim 1, wherein the display device comprises an LCD drive circuit, a backlight drive circuit, and a display panel.
 5. The device as claimed in claim 1, wherein the warning unit is connected to an alarm device.
 6. The device as claimed in claim 5, wherein the alarm device comprises a buzzer.
 7. The device as claimed in claim 1, wherein the power supply device comprises a direct-current battery set.
 8. A refrigerant sensing element comprising: an enclosure, having an end forming a connector adapted to connect to a supply of refrigerant to be detected, the enclosure forming an interior chamber, which communicates the connector with a pressure-dropping necked passage to convey the refrigerant to be detected, in a pressure dropped condition, into the chamber; a pressure detection chip, arranged at a top of the chamber to detect pressure of refrigerant supplied into the chamber of the enclosure; and a thermocouple, arranged at the top of the chamber to detect temperature of the refrigerant supplied into the chamber of the enclosure.
 9. The sensing element as claimed in claim 8, wherein the enclosure has an end forming an inner-threaded opening in which a thread is formed.
 10. The sensing element as claimed in claim 9 further comprising a threaded closing member engaging and retained in the inner-threaded opening.
 11. The sensing element as claimed in claim 8, wherein the pressure detection circuit and the thermocouple are mounted on a control circuit board.
 12. The sensing element as claimed in claim 8, wherein the pressure detection chip has a detection end and terminals on the opposite end.
 13. The sensing element as claimed in claim 8, wherein the pressure detection chip is connected to constant current source.
 14. The sensing element as claimed in claim 8, wherein the thermocouple has terminals. 